Tantalum-containing material removal

Abstract

Methods are described herein for etching tantalum-containing films with various potential additives while still retaining other desirable patterned substrate portions. The methods include exposing a tantalum-containing film to a chlorine-containing precursor (e.g. Cl 2 ) with a concurrent plasma. The plasma-excited chlorine-containing precursor selectively etches the tantalum-containing film and other industrially-desirable additives. Chlorine is then removed from the substrate processing region. A hydrogen-containing precursor (e.g. H 2 ) is delivered to the substrate processing region (also with plasma excitation) to produce a relatively even and residue-free tantalum-containing surface. The methods presented remove tantalum while retaining materials elsewhere on the patterned substrate.

The invention claimed is: 
     
       1. A method of etching tantalum-containing material from a substrate, the method comprising:
 placing the substrate into a substrate processing region, wherein the substrate comprises exposed tantalum-containing material, exposed titanium nitride, and exposed hafnium oxide; 
 etching the tantalum-containing material and the titanium nitride by flowing diatomic chlorine into the substrate processing region while forming a local plasma from the diatomic chlorine and forming chlorine plasma effluents, wherein etching the tantalum-containing material and the titanium nitride further comprises accelerating the chlorine plasma effluents towards the substrate by biasing the local plasma relative to the substrate, wherein etching the tantalum-containing material and the titanium-nitride leaves a residue on a remaining portion of the substrate, and wherein the hafnium oxide is substantially maintained during the etching; 
 removing the residue from the remaining portion of the substrate by flowing a hydrogen-containing precursor into the (same) substrate processing region while forming a hydrogen local plasma from the hydrogen-containing precursor to form hydrogen-containing plasma effluents, wherein flowing of the hydrogen-containing precursor occurs after flowing the diatomic chlorine; and 
 removing the substrate from the substrate processing region. 
 
     
     
       2. The method of  claim 1  wherein the tantalum-containing material further comprises silicon, carbon, and aluminum. 
     
     
       3. The method of  claim 1  wherein a temperature of the substrate while removing the tantalum-containing material is between 80° C. and 450° C. while removing tantalum-containing material from the substrate. 
     
     
       4. The method of  claim 1  wherein the substrate is maintained at a same substrate temperature while etching the tantalum-containing material and removing the residue. 
     
     
       5. A method of etching tantalum-containing material from a substrate, the method comprising:
 placing the substrate into a first substrate processing region, wherein the substrate comprises tantalum-containing material and an overlying tantalum oxide; 
 reducing the overlying tantalum oxide and exposing the tantalum-containing material and a titanium nitride by flowing a hydrogen-containing precursor into a first substrate processing region housing the substrate while forming a hydrogen plasma in the first substrate processing region; 
 placing the substrate into a second substrate processing region; 
 etching the tantalum-containing material and the titanium nitride by flowing a chlorine-containing precursor into the second substrate processing region while forming a local plasma from the chlorine-containing precursor to form chlorine-containing plasma effluents, wherein forming the local plasma further comprises accelerating the chlorine-containing plasma effluents towards the substrate by biasing the local plasma relative to the substrate, wherein the second substrate processing region is maintained between about 3 Torr and about 20 Torr during the etching; 
 flowing a hydrogen-containing precursor into the second substrate processing region while forming a second hydrogen plasma in the second substrate processing region, wherein flowing of the hydrogen-containing precursor occurs after flowing the chlorine-containing precursor; and 
 removing the substrate from the second substrate processing region. 
 
     
     
       6. The method of  claim 5  wherein a temperature of the substrate while removing the tantalum-containing material is between 175° C. and 275° C. while removing tantalum-containing material from the substrate. 
     
     
       7. The method of  claim 5  wherein the tantalum-containing material has at least 40% atomic percent tantalum. 
     
     
       8. The method of  claim 5  wherein the tantalum-containing material has at least 50% atomic percent tantalum. 
     
     
       9. The method of  claim 5  wherein the tantalum-containing material comprises tantalum, silicon, carbon and aluminum. 
     
     
       10. The method of  claim 5  wherein the hydrogen-containing precursor comprises Hz. 
     
     
       11. The method of  claim 5  wherein the first substrate processing region and the second substrate processing region are the same substrate processing region. 
     
     
       12. The method of  claim 5  wherein a pressure within the first substrate processing region and the second substrate processing region is between 0.01 Torr and 10 Torr during one or more of flowing the hydrogen-containing precursor, flowing the halogen-containing precursor or flowing the hydrogen-containing precursor. 
     
     
       13. The method of  claim 5  wherein forming the hydrogen plasma comprises applying a local capacitive plasma RF power between a showerhead and the substrate. 
     
     
       14. The method of  claim 5  wherein a processing temperature of the substrate is greater than 80° C. during the etching of the tantalum-containing material. 
     
     
       15. A method of etching tantalum-containing material and tantalum oxide, the method comprising:
 transferring a substrate into a substrate processing region, wherein the substrate comprises tantalum-containing material and a thin tantalum oxide layer thereon; 
 removing the thin tantalum oxide layer by flowing a hydrogen-containing precursor into the substrate processing region while forming a local plasma from the hydrogen-containing precursor; 
 etching the tantalum-containing material and an exposed titanium nitride by flowing a chlorine-containing precursor into the substrate processing region while forming a chlorine plasma from the chlorine-containing precursor to form chlorine-containing plasma effluents, wherein etching the tantalum-containing material occurs after removing the thin tantalum oxide layer, wherein removing the tantalum-containing material leaves a residue on a post-etch surface of the tantalum-containing material, wherein the substrate processing region is maintained at a pressure between about 3 Torr and about 20 Torr during the etching, wherein the substrate further comprises an exposed hafnium oxide, and wherein the exposed hafnium oxide is substantially maintained during the etching; 
 removing the chlorine-containing precursor by purging the substrate processing region with an inert gas; 
 removing the residue from the post-etch surface by flowing a second hydrogen-containing precursor into the substrate processing region while forming a second local plasma from the second hydrogen-containing precursor; and 
 transferring the substrate out of the substrate processing region. 
 
     
     
       16. The method of  claim 15  wherein forming a chlorine plasma comprises accelerating the chlorine-containing plasma effluents towards the substrate by biasing the chlorine plasma relative to the substrate. 
     
     
       17. The method of  claim 15  wherein the substrate is maintained at a same substrate temperature during the removal of the thin tantalum oxide layer and the removal of the tantalum-containing material. 
     
     
       18. The method of  claim 15  wherein the substrate remains inside the substrate processing region throughout the method.